The present invention relates to an information search apparatus and method for searching information on the basis of an input query word. More specifically, the present invention relates to an information search apparatus and method for managing a plurality of kinds of multimedia information, and searching the managed multimedia information for desired multimedia information, and a computer readable memory.
A conventional information search apparatus, which searches multimedia information, e.g., image information, makes a search using data (keywords) derived from subjective evaluation results of one or a plurality of persons for test images, physical image features extracted from images, and the like.
When an image is searched for using a keyword, a required image is obtained by matching a given keyword with that corresponding to the image. Also, a scheme for obtaining an image, that cannot be obtained by full-word matching with an input keyword, by matching not only the input keyword but also an associated keyword associated with the input keyword with a keyword corresponding to an image, is proposed. Furthermore, a search scheme which obtains an image with similar color information by detecting a correspondence between the input keyword and color information using, e.g., color information of images is proposed.
In the image search using keywords, an impression that a person receives upon watching an image, or key information linked with the impression is appended to image information and is used in search. As the key information, words that express impressions evoked by images such as xe2x80x9cwarmxe2x80x9d, xe2x80x9ccoldxe2x80x9d, and the like, and words that represent objects in drawn images such as xe2x80x9ckittyxe2x80x9d, xe2x80x9cseaxe2x80x9d, xe2x80x9cmountainxe2x80x9d, and the like are appended as keywords. Also, local image feature components on drawn images are subjectively evaluated and are often appended as key information. For example, information that pertains to a color such as xe2x80x9credxe2x80x9d, xe2x80x9cbluexe2x80x9d, and the like, information that pertains to a shape such as xe2x80x9croundxe2x80x9d, xe2x80x9ctriangularxe2x80x9d, xe2x80x9csharpxe2x80x9d, and the like, and information that pertains to a texture such as xe2x80x9csandyxe2x80x9d, xe2x80x9csmoothxe2x80x9d, and the like are expressed using words and icons, are appended to images as key information, and are used in search.
In a system in which physical image feature amounts are extracted from images, and are used in image search, image features include local colors painted on images, overall color tones, and shapes, compositions, textures, and the like of objects on drawn images. An image feature amount is extracted from segmented regions or blocks obtained by segmenting the overall image into regions based on color information, or segmenting the image into blocks each having a given area, or is extracted from the entire image. Physical image features include, e.g., color information, density distribution, texture, edge, region, area, position, frequency distribution, and the like of an image.
However, in the above search scheme, when an image including a keyword that matches the input query word is searched for, images which do not match the search request of the searcher are often obtained. Especially, when an image search is made using an abstract query word such as a xe2x80x9crefreshingxe2x80x9d image, images found by the search are limited. To solve this problem, a search may be made by unfolding the query word xe2x80x9crefreshingxe2x80x9d to keywords which are associated with that query word. However, when such scheme is used, images which are not xe2x80x9crefreshingxe2x80x9d may be mixed in search results.
In this manner, the operator cannot designate query conditions for obtaining a desired search result with respect to a search request indicated by the input keyword, and cannot obtain an intended search result. For example, even when the operator wants to find only images having xe2x80x9crefreshingxe2x80x9d feature patterns with respect to a search request xe2x80x9crefreshingxe2x80x9d, images having content words associated from the search request xe2x80x9crefreshingxe2x80x9d such as a music score of a xe2x80x9crefreshingxe2x80x9d music, a xe2x80x9crefreshingxe2x80x9d athletexe2x80x9d, and the like, are presented, i.e., images which do not match the search request are presented.
In place of a query word, a query image may be input, and a search may be made using its feature amount. However, in this case, a query image which reflects the searcher""s will must be prepared, and it is difficult to select a query image, resulting in poor operability.
The present invention has been made in consideration of the above-mentioned problems, and has as its object to provide an image search method and apparatus which can extract the information wanted with high precision with respect to an input query word.
In order to achieve the above object, according to one aspect of the present invention, there is provided an information search apparatus for searching information based on an input query word, comprising first search means for determining a query keyword on the basis of the query word, and searching information on the basis of the query keyword, second search means for determining a feature amount corresponding to the query word, and searching information on the basis of the feature amount, setting means for setting a search weight to be assigned to search results of the first and second search means, and integration means for integrating search results obtained by the first and second search means in accordance with the search weight set by the setting means.
In order to achieve the above object, according to another aspect of the present invention, there is provided an information search method for searching information based on an input query word, comprising the first search step of determining a query keyword on the basis of the query word, and searching information on the basis of the query keyword, the second search step of determining a feature amount corresponding to the query word, and searching information on the basis of the feature amount, the setting step of setting a search weight to be assigned to search results in the first and second search steps, and the integration step of integrating search results obtained in the first and second search steps in accordance with the search weight set in the setting step.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.